Water Hardness

Water Harness

PPM
Parts Per Million
(mg/l)

GPG
Grains Per
Gallon US
°dh
German Hardness

°fH
French Hardness

Very Soft 1 - 70 1.0 - 4.2 1.0 - 4.0 0.1 - 7.0
Soft 71 - 125 4.3 - 7.2 4.1 - 7.9 7.1 - 12.5
Medium Hard 126 - 250 7.3 - 22 8.0 0 14 12.6 - 25
Hard 251 - 500 23 - 30 15 - 24 25.1 - 50
Extremely Hard 501+ 31+ 16+ 51+